The present disclosure claims priority from Korean Patent Application No. 11662/2003, filed Feb. 25, 2003, the subject matter of which is incorporated herein by reference.
1. Field of the Invention
Embodiments of the present invention may relate to a sending end of a mobile communication terminal. More particularly, embodiments of the present invention may relate to an apparatus and method for monitoring a state of an antenna of a mobile communication terminal.
2. Background of Related Art
A mobile station may provide both a second-generation mobile communication service and a third-generation mobile communication service. Multimode terminals may provide a multimedia service as well as a voice service and a data service.
FIG. 1 illustrates a transmitter of a multimode mobile station according to an example arrangement. Other arrangements are also possible. As shown in FIG. 1, the transmitter of the multimode mobile station may include a variable gain amplifier 10, a power amplifier 20, a duplexer 30, a communication band switch 40 and an external antenna 50. The variable gain amplifier 10 may vary an amplification gain of a transmission signal. The power amplifier 20 may power-amplify an output signal of the variable gain amplifier 10. The duplexer 30 may transmit the power-amplified transmission signal to a transmission path. The communication band switch 40 may output a Wideband Code Division Multiple Access (WCDMA) signal output from the duplexer 30 to an external antenna 50 and provide a transmission path of a GSM (Global System for Mobile communication) signal and a DSC (Digital Cellular Service) signal.
FIG. 2 shows a communication band switch according to an example arrangement. Other arrangements are also possible. As shown, the communication band switch 40 includes a diplexer 41, a first switch 42, a second switch 43 and a third switch 44. The diplexer 41 may separate signals with different frequencies through low-pass filtering and high-pass filtering. The first switch 42 may transmit and receive the GSM signal by switching according to a band switching control signal input to a band switching control terminal. The second switch 43 may transmit and receive the DCS signal according to the band switching control signal. The third switch 44 may transmit the WCDMA signal by switching according to the band switching control signal.
The above-described transmitter of the multimode mobile station may operate as follows. The WCDMA transmission signal may be input to the power amplifier 20 through the variable gain amplifier 10. The power amplifier 20 may power-amplify the WCDMA transmission signal. The duplexer 30 may output the power-amplified WCDMA transmission signal to the external antenna 50 through the communication band switch 40.
An output level of the transmitter of the mobile station may be set by standards. Since the external antenna 50 protrudes outwardly from the terminal, the external antenna 50 may be easily broken or cracked, and thus, there is a high possibility that the antenna can be electrically malfunctioned. In such a case, an output level of the mobile station may be sharply degraded while a current consumption of the power amplifier 20 is considerably increased.
An increase in the current consumption of the power amplifier 20 may result in physical damage to elements that affect an output terminal matching, such as the duplexer 30, the communication band switch 40 and the external antenna 50. This may also shorten a life span of the battery of the mobile station.
Installation of an isolator in the mobile station may reduce the physical damage to the elements affecting the output terminal matching of the mobile station, but in this case, an isolator insertion loss may be inevitably made, causing more current consumption of the power amplifier than the mobile station without having the isolator and resulting in a shortening of the life span of the battery.